Fix compilation with older MinGW versions

The __MINGW_PRINTF_FORMAT constant has been defined back in 2012
https://sourceforge.net/p/mingw-w64/mingw-w64/ci/77bc5d6103b5fb9f59fbddab1583e69549913312/

However older toolchains are still around and some user reported the
following compilation failure:

  flash.h:336:1: error: '__MINGW_PRINTF_FORMAT' is an unrecognized format function  type [-Werror=format=]
    __attribute__((format(__MINGW_PRINTF_FORMAT, 2, 3)));

Fix this by defining the constant when it isn't already; the change does
not affect other compilers because it's guarded by "#ifdef __MINGW32__".

Setting  __MINGW_PRINTF_FORMAT to gnu_printf is exactly what newer MinGW
versions do when __USE_MINGW_ANSI_STDIO is defined, which it is in
flashrom Makefile.

Change-Id: I48de3e4303b9a389c515a8ce230282d9210576fd
Tested-by: Miklos Marton <martonmiklosqdev@gmail.com>
Signed-off-by: Antonio Ospite <ao2@ao2.it>
Reviewed-on: https://review.coreboot.org/25130
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>

0 files changed, 0 insertions, 0 deletions